Process of and apparatus for extracting metals from ores



'INo Model.)

W. E. INGLIS. PROCESS OP AND APPARATUS POR EXTRAGTING METALS PROM ORES.

Patlented Dec. 28, 1897.

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Afm/mfr UNITED STATES PATENT OFFICE.

WALTER E. INeLIs, OE MOUNT VERNON, NEW YORK.

PROCESS 0F AND APPARATUS FOREXTRACTING METALS FROM GRES.

SPECIFICATION forming part of Letters Patent No. 596,458, dated December 28, 1897.

Application filed April zo, 1896.

. To @ZZ whom it may concern:

Be it known that I, WALTER E. INGLIS, residing at Mount Vernon, in the county of W'estchester and State of New York, have invented certain new and useful Improvements in the Process of and Apparatus for Extraction of Metals from Ores by the Use of Electricity and I do hereby declare the following to be a full, clear, and exact description of the process and apparatus, such as will enable others skilled in the art to which it appertains to make use of the same.

This invention relates to the recovery or separation of metals, precious or other, from their ores, its application not being'contined to any particular ore or metal. In the following speciiication I have described it as applied to the extraction of tin from its ores.

I take a crucible made of a suitable nonelectroconducting material and first place therein a quantity of metallic tin sufficient when melted to cover the bottom of the crucible. This mass of molten metal is connected to the negative pole of a dynamo or other convenient source of electricity by means of a wire or other suitable conductor and forms the cathode of the electrolytic bath wherein the ore is to be treated. I next place in the crucible a suflicient quantity of chlorid of sodium or other substance capable of being decomposed by the electric current and containing a morel electropositive element than the metal in the ore to be treated. This forms the electrolyte and is kept in a molten state at a temperature above the volatile point of metallic sodium at rst by means of outside heat, but afterward the electric current is passed through it in such quantity thatA enough heat is developed in its passage to keep the whole bath at the proper temperature.- In this bath and on top of the molten cathode and in direct contact with it is placed a quantity of properly crushed aud concentrated tin ore, the metal of which it is purposed to extract. The anodes of the electric bath consist of one or more carbon rods which reach down into the crucible and are immersed for part of their length in the electrolyte of fused salt. These anodes are supported in any convenient manner and are connected by a conductor to the positive pole of the dynamo or other source of electricity. Acontinuous current of elec- Serial No. 588,291l- (No model.)

tricity at about five volts and of sufficient quantity to maintain fusion is passed through the bath. This decomposes the electrolyte, separating it into its elements, chlorin and sodium, the chlorin passing from the bath at the carbon anodes and either escapes into the atmosphere or is conducted into a flue and disposed of as it may be convenient. The sodium, being the electropositive element of the electrolyte, passes to the cathode at the bottom of the bath, and as the temperature is above the volatile point of sodium is volatilized, and having more affinity for the oxygen which is in combination with the tin in the ore unites with it, forming oXid of sodium, and displacing the tin sets itfree in a molten state. The tin thus separated from the oxygen sinks into and increases the layer of melted tin below.

In order to utilize in the reduction of ore all the sodium produced by the electric current and also to prevent the sodium from alloying itself with the metal produced, I allow the metal after reduction to percolate in a finelydivided molten condition at a temperature above the volatile point of sodium through ore which has not been acted on. This is ac complished by raising the molten surface of metal which serves as the cathode above the bottom of the crucible. This leaves a groove all around the raised portion, ending in the tap-hole. This groove contains ore not yet acted on, and the metal in the elevated cath? ode being constantly increased by addition of reduced metal overiiows and percolates through the interstices ofthe ore. By this method any sodium which may have alloyed itself with the reduced metal is by reason of the high temperature, assisted by the iinely- .divided state of the metal, rendered volatile and reduces the fresh ore which is in contact with it. Another reason for raising the cathode above the main body of reduced metal is that any slag that may be formed during the operation, consisting of silicates heavier than the electrolyte and which by their gathering around the cathode would interfere with the proper operation of the bath and tend to contaminate it, will fall away from the cathode and remain in the groove around it above the reduced metal and, as the metal is tapped, will follow it out of the'crucible and be dis- IOG posed of as most convenient. As the operation continues the bath is gradually changed from chlorid of sodium to oxid of sodium, which under the action of the electric current is resolved into oxygen and sodium, the Oxy-- the utilization of all the reducing agents pro;

duced by the electric current.

The drawings herewith form specification.

Figure l is a central vertical section. Fig. 2 is a plan view; and Fig. 3 is a section corresponding to Fig. l, but showing a modification.

In all the Iigures similar letters of reference part of this indicate corresponding parts of the apparatus.

I provide a furnace of fire-brick or other suitable material provided with a gas-burner or other conveniently-used source of heat, which, however, is mainly essential at the commencement of the operation, the current being of such quantity that the heat developed by the resistance of the bath is sufficient to keep it in a state of fusion.

Within the furnace I mount a crucible A, having at the bottom an elevated central portion A', the top of which is hollowed to constitute a basin a, preferably of circular form, adapted to receive and retain a melted mass of metal which presents an extended surface.

The rim A2 around this central pool shouldl be as nearly level as possible,`so that thel overtiow may extend over a large portion of the surface as the melted metal accumulating in the basin ct overflows to gather in the cir-` I provide for tapping cular groove a. below. out the metal from this groove through a tap a2, formed in the extension, as shown in Fig. l.

B is a support, of iron or other suitable conducting material, extending across the top of the crucible and carrying a number of carbons B, which may be shifted downward inz the support from time to time as consumed. These connect through the support and by, means of a wire B2 with the positive pole of a dynamo M, which may be at any convenientg distance and driven by a steam-engine or, other power, so as to afford a proper current of electricity.

terior 4of the crucible. electrolyte.

D is a hollow shield, which may be of the same materia-l as the crucible, open at the top and bottom and extending above the surface of the electrolyte. The lower end of this shield -is flared, as indicated by D'. Through this shield I introduce the broken ore G either constantly or at short intervals, so as to maintain it nearly or quite filled. This shield keeps the volatile sodium separate from the general mass of the electrolyte and confines it to the unreduced body of ore within the shield. This construction also prevents the ore from ever being received in the general body of the crucible in such quantity as to come in contact with the carbons.

A quantity of tin, sufficient when melted to fill the cup-like cavity or basin a, is introduced therein and when the apparatus is in operation'forms a circular extended surface of highly-conducting material which serves as the cathode. A conductor E, of metallic wire, or it may be of other material, extends upward from this melted tin througha nonconducting sheath F, which may be of the same material as the crucible or of any other suitable material, and connects to the negative pole of the dynamo. When the apparatus is in operation, there isa constant flow of the current fromthe carbon down through the electrolyte to the cathode and thence upward through the conductor back to the d ynamo.

Tin ore G, properly crushed and concentrated, being supplied through the liberal space Within the shield ymy apparatus maintains a covering of lore not only over the cathode, but also over the whole bottom of the interior of the Crucible.

A current at five volts serves to decompose the electrolyte, the chlorin .passing from the bath at the anode and the sodium `going to the cathode, there substituting itself for the oxygen of the ore, as already described. By this reaction oxid of sodium is produced, which remains in the bath, the quantity of which constantly increases until the whole bath is changed to fused oxid of sodium, which, like vthe chlorid, is decomposed, the sodium as before acting on the ore and the oxygen passing from the bath at the anode. As .oxid of sodium unites with stannic oxid to form fusible sodium stannate, this salt may be formed as an intermediate product, but asit is easily decomposed under .the `action of the electric current into its elements sodium, tin, and oxygen-it will result finally as described, the tin and sodium goingto the cathode and the oxygen passing from the bath at the anode. Thus it will be seen that I provide a continuous process of separat-ing metals from the elements associated with `them I supply asufcient quantity of chlorid of g sodium (common salt) to make, when fused, a bath which shall occupy all the otherwise: unfilled space in the lower portion of the in-f This serves as thely `in their ores, the associated elemen-t first passjing from the ore to the electrolyte under .the

-reducing `action of an element of asuperior .electropositive affinity derived from the elec- -trodecomposition of theelectrolyte itself and -iinally passing from kthe bath at the anode under the actionof the electric current. The tin after its separation sinks into the molten surface of the cathode, causing it to overiiow Aand pass in a finely-.divided condition at .the temperature of the bath through ore not as IOO IIO

yet acted upon, as already explained. This will prevent any sodium remaining alloyed with the reduced metal. Any silicious material in the ore not capable of reduction will beconverted into fusible silicates and being heavier than the electrolyte will fall away from the cathode and lie on top of the reduced metal and will be tapped o after it.

When the ore to be operated on is itself a tolerably good conductor of electricity, it can serve as the cathode, even without thelayer of reduced metal being in contact therewith, by simply having the conductor F come in contact with the heated ore for a sufficient distance, as shown in Fig. 3; but for ores of ordinary conductivity I prefer to work with the reduced metal and the ore, b'oth together to serve as the cathode.

I claim as my inventionl. The within-described method of extracting metals from ores or compounds, consisting in electrically decomposing an electrolyte, comprising an agent of more electropositive character than that of the metal in the ore, or compound and causing the freed agent to displace the metal in the ore or compound, and afterward passing the reduced metal at a high temperature in contact with a body of untreated ore or compound to free it from residual traces of said agent, all substantially as, and for the purpose set forth.

2. An apparatus for electrically extracting metals, consisting of the combination of a Crucible adapted to contain metallic compounds, an electrolyte, and refractory anodes B, means for retaining in the interior of the Crucible, an extended surface of melted metal,

elevated above the main portion of the bottom and forming the cathode, the rim A2 being adapted to distribute the overiiow so as to present to further unreduced ore, an extended surface of melted metal as it descends, and a receptacle for receiving the melted overflowings from the rim A2, and provided with a plug substantially as, and for the purpose set forth.

. 3. In apparatus for reducing metals by aid of electricity, the combination of la Crucible andinclosing furnace, provisions for generating heat at the commencement of the operation, provisions for tapping out the reduced metals and for supplying more material, and

a source of electricity, conductors therefrom, and electrodes B connected to serve as the anode, an elevated pool of melted metal a to an electric current, the sodium, and causingthe freed nascent sodium to separate the tin without fusing said tin and finally collecting the tin.

In testimony that I claim the invention above set forth I aix my signature in presence of two witnesses.

WALTER' n. iNeLis.

Witnesses:

J. B. CLAUTICE, M. F. BoYLE. 

